ISSN print edition: 0366-6352 ISSN electronic edition: 1336-9075 Registr. No.: MK SR 9/7 Published monthly

Mechanism of thermal decomposition of cobalt acetate tetrahydrate

T. Wanjun and C. Donghua

Hubei Key Laboratory for Catalysis & Material Science, College of Chemistry & Material Science, South-Central University for Nationalities, Wuhan, 430074, China

E-mail: tangmailbox@126.com

Received: 16 October 2006  Revised: 4 January 2007  Accepted: 2 February 2007

Abstract: The thermal decomposition of cobalt acetate tetrahydrate (Co(CH₃COO)₂ · 4H₂O) has been studied via thermogravimetric (TG) analysis, in situ X-ray powder diffraction (XRD), and Fourier transform infrared spectroscopy (FTIR). The results of TG and XRD showed that the parent salt melted and then the dissolved crystalline water was vaporized in two steps. The dehydration process was followed by a major step concerning the decomposition of the acetate group, leading to basic acetate as an intermediate, which then produced CoO and Co in N₂ and H₂ atmosphere, respectively. Three decomposition intermediates Co(CH₃COO)₂ · 0.5H₂O, Co(CH₃COO)₂, and Co(OH)(CH₃COO) were presumed. In situ XRD experiments revealed that the intermediate basic acetate was poorly crystallized or even amorphous. Evolved gases analysis indicated that the volatile products of acetate decomposition were water vapor, acetic acid, ethylenone, acetone, and CO₂. A detailed thermal decomposition mechanism of Co(CH₃COO)₂ · 4H₂O was discussed.

Keywords: IR spectroscopy - thermogravimetry - in situ XRD - decomposition - cobalt acetate tetrahydrate

Full paper is available at www.springerlink.com.

DOI: 10.2478/s11696-007-0042-3

Chemical Papers 61 (4) 329–332 (2007)